Current transformers are essential electronic components for various kinds of electric appliances. Generally, a current transformer is used for measurement of electric currents. When an electric current in a circuit is too high, a current transformer produces a reduced current accurately proportional to the electric current in the circuit.
A conventional current transformer comprises a bobbin, a magnetic core assembly, a primary winding coil and a secondary winding coil. The primary winding coil and the secondary winding coil are separately wound around a winding section of the bobbin. The magnetic core assembly is partially embedded into the winding section of the bobbin. When an electric current flows in the primary winding coil, a magnetic field is produced in the magnetic core assembly and an induced current is generated in the secondary winding coil.
As the demand on the electric conversion efficiency of electronic device is gradually increased, the safety regulations become more stringent. In other words, the electrical safety distance between the primary winding coil and the secondary winding coil and the electrical safety distance between the magnetic core assembly and the secondary winding coil need to be long enough for the current transformer. Since the primary winding coil and the magnetic core assembly of the conventional current transformer are not sufficiently isolated from the secondary winding coil, the electrical safety distance between the primary winding coil and the secondary winding coil and the electrical safety distance between the magnetic core assembly and the secondary winding coil are too short to meet the safety requirement.
Therefore, there is a need of providing an improved current transformer so as to obviate the drawbacks encountered from the prior art.